# Installing required jar files and adding them to the classpath

To use the Network Server and network client driver, add the following jar file to your server classpath.

- `derbyrun.jar`

Adding this file to your classpath has the effect of including all of the Derby classes in your classpath. These classes are in the following jar files, which you can also add to your classpath separately:

- `derbynet.jar`

  This jar file contains the Network Server code. It must be in your classpath to start the Network Server.

- `derby.jar`

  This jar file contains the Derby database engine code. It must be in the classpath in order for the Network Server to access Derby databases. `derby.jar` is included in the `Class-Path` attribute of `derbynet.jar`'s manifest file. If you have `derbynet.jar` in the classpath and `derby.jar` is in the same directory as `derbynet.jar`, it is not necessary to include `derby.jar` explicitly.

- `derbyclient.jar`

  This jar file contains the Derby Network Client JDBC driver that is necessary for communication with the Network Server. It must be in the classpath of the application on the client side in order to access Derby databases over a network.

- `derbytools.jar`

  This jar file contains the standard Derby tools, such as `ij`, `sysinfo`, and `dblook`. The `derbytools.jar` file is not needed in your classpath to run the Network Server, but it is automatically included by `derbyrun.jar`.

- `derbyoptionaltools.jar`

  This jar file contains additional Derby tools, such as the Lucene plug-in. The `derbyoptionaltools.jar` file is not needed in your classpath to run the Network Server, but it is automatically included by `derbyrun.jar`.

All of the jar files are in the `$DERBY_HOME/lib` directory.

Derby provides script files for setting the classpath to work with the Network Server. The scripts are located in the `$DERBY_HOME/bin` directory.

- `setNetworkClientCP.bat` (Windows)
- `setNetworkClientCP` (UNIX)
- `setNetworkServerCP.bat` (Windows)
- `setNetworkServerCP` (UNIX)

See Managing the Derby Network Server and Getting Started with Derby for more information on setting the classpath.
Parent topic: Using the Network Server with preexisting Derby applications
Related concepts
The Network Server and Java Virtual Machines (JVMs)
Accessing the Network Server by using the network client driver
Accessing the Network Server by using a DataSource object
XA and the Network Server
Using the Derby tools with the Network Server
Differences between running Derby in embedded mode and using the Network Server
Related tasks
Starting the Network Server
Shutting down the Network Server
Obtaining system information
Setting port numbers